1. Field of the Invention
The invention relates to a structure for optically coupling at least one optical conductor with an optical input or output of an optical device, the structure including a carrier wherein the optical conductor is embedded so that it has at least one locally bent part reaching an outer surface of the carrier and forming there at least one optical contact point to which the optical input or output of the device has to be coupled.
The above optical device may be either an active electro-optical component such as a light emitting diode, a laser diode, an optical switch, a detector etc or a group of such components or a passive component such as another optical conductor or ribbon-shaped optical cable, or an optical coupler, etc., or a group of such passive components. The optical conductor to be connected therewith may be an optical fiber, more particularly an optical fiber arranged on a circuit board on which the above device should be mounted or to which it should be connected.
2. Background Information
A structure of the above type is described in the European patent application No 91200170.8 (W. DELBARE-J. VANDEWEGE 2-2) in the name of the Applicant. In this patent application the carrier with embedded optical fibers and hence provided with optical contacts at its outer side, forms part of a circuit board. The optical input and/or output of the optical device to be mounted on the board should be very accurately positioned with respect to the optical contacts in order to realize an optical transmission of light through these contacts. For multimode applications, the positioning accuracy should preferably be 5 micrometers or better, while for monomode applications this accuracy should preferably be better than one micrometer.
In this known structure, this accuracy can only be obtained by active positioning, meaning that the optical device is activated and that this device and the carrier with the optical contact point are displaced with respect to each other until an optimal amount of optical power is transmitted through the optical contact. Depending on the type of optical device an outside light source or an outside light detector is thereby required. With some devices, such as an optical amplifier, both are necessary. This is also the case with passive optical devices, such as optical couplers or part of optical couplers. This active positioning is therefore complex and time consuming. Moreover, with optical devices having a plurality of inputs and outputs the active positioning does not provide good results if the distances between the optical fibers embedded in the carrier and therefore between the optical contact points, are not accurate.